Compton generator

[4] Arthur Compton (Nobel Prize in Physics in 1927) published it during his fourth year at the College of Wooster in 1913.

[5] A Compton generator is a circular hollow glass ring tube shaped like a doughnut, the inside of which is filled with water.

[1] If the ring lies flat on the table, the water in the ring is stationary, and it is then turned over by rotating itself 180 degree around a diameter, such that it again lies flat on the table surface, which is horizontal.

The result of the experiment is that the water moves with a certain constant drift velocity around the tube after the doughnut has been rotated.

If there were no friction with the walls, the water would continue to circulate indefinitely.

[6] Compton used small droplets of coal oil mixed in the water to measure the drift velocity under a microscope.

Second the ring is then quickly rotated by 180° around its East-West diameter and stopped, such that it again lies flat on the table surface, which is horizontal.

This is derived by first integrating the torque due to the Coriolis force around the ring, then integrating the torque over the time it takes for the ring to flip, to obtain the change in angular momentum.

Compton used this measured drift velocity to determine his latitude to within 3% accuracy.

By careful methods he could observe the effect in a ring with a radius of only 9 inches (23 cm).

In the original report, Compton used a ring of 1 meter in radius at the College of Wooster (latitude 41 degrees).

Arthur Compton was experimenting by the Compton Generator. The box is constructed out of asbestos to minimize the temperature differential across the ring, which causes errors since it creates convectional current . There is a further screen of asbestos in front of Compton in order to prevent his breath from hitting the box of asbestos.
Construction of Compton generator.